Transistor of particular type manufactures by the same company come out of production with different values of several parameters . Hence when a transistor in a given circuit is replaced by another of the same type, there is some variation in transistor parameters
Thermal stability
Ic=βIb+(1+β)Iceo
When there is a change in temperature ,there is a marked change in reverse saturation current Ico ,thus for every 10 degree rise in temperature Ico get double
Biasing(Need for biasing)
Derived features of biasing method used as transistor biasing circuits should be:-
1)To establish conviniently the operating point in the middle of active region of chara
2)To make the operating point independent of temperature variation
3)To establish the collector current against temperature variation
Ic=βIb+(1+β)Iceo
When there is a change in temperature ,there is a marked change in reverse saturation current Ico ,thus for every 10 degree rise in temperature Ico get double
Biasing(Need for biasing)
Derived features of biasing method used as transistor biasing circuits should be:-
1)To establish conviniently the operating point in the middle of active region of chara
2)To make the operating point independent of temperature variation
3)To establish the collector current against temperature variation
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